Original Adventures Reincarnated #4 - The Lost City - Rules of Play says:
This tome is an homage to the original dungeon crawl and sandbox setting first explored decades ago as B4: The Lost City. Herein, you will find high-quality scans of the original Basic edition adventure module, plus commentary by a variety of gaming luminaries. This includes an interview with Harold Johnson, the module’s original developer, who also discusses his work on playtesting, Dragonlance, and other TSR titles. Also, herein is a full fifth edition conversion of the original adventure as well as brand new additional dungeons, such as the fully developed lower pyramid, additional details on the Lost City itself, and the dreaded Lower Catacombs.